ATM 103: Module 7.3- Discussion of Past Storms and Observation

Wind Damage

-Destruction caused by hurricane's strong winds

-High winds turn objects into projectiles

-Can spawn tornadoes, causing localized damage

-Impacts buildings, vehicles, trees, and infrastructure

-One of the primary hurricane hazards

Hurricane Sandy

-North Atlantic hurricane causing East Coast flooding

-Flooding mainly from storm surge

-Unusual track toward East Coast due to atmospheric features

-Large wind field; extratropical at landfall

-Extensive damage to coastlines, infrastructure, and power

Hurricane Katrina

-Category 5; catastrophic Gulf Coast damage, esp. near New Orleans

-Maximum winds 175 mph; made U.S. landfall twice

-New Orleans landfall: Category 3

-Area vulnerable to storm surge & flooding (below-sea-level terrain)

-Post-Katrina protections designed for "once in 100-year" storm

Typhoon Haiyan

-One of the most intense tropical cyclones recorded; struck Philippines

-Maximum winds: 195 mph; extreme destruction

-Damage: ~$2.86B USD

-Death toll: >6,300

Hurricane Observations

-Satellites: track location, size, cloud patterns, rainfall

-Aircraft reconnaissance: measure wind, pressure, temperature

-Radar: detect rainfall, wind patterns, storm structure near land

-Intensity estimation: central pressure & max sustained winds

-Combining satellite, aircraft, and radar data improves assessment

Hurricane Observation Challenges

-Surface measurements rare, esp. in eyewall

-Upper-level winds stronger than surface winds

-GPS dropwindsondes measure pressure, wind, humidity

-Accurate data crucial but difficult for forecasting

Aircraft Reconnaissance

-Planes fly through/around hurricanes to collect data

-Measures winds, pressure, temperature, storm structure

-Releases GPS dropwindsondes for vertical profiles

-Data mainly collected near land

-Crucial for estimating intensity & structure

Radars and Buoys

-Doppler radar tracks storms within ~320 km of coast

-Measures wind speed, direction, precipitation

-Data buoys: fixed ocean instruments, record oceanic & atmospheric data

-Essential for forecasting & tracking

Satellite Observations

-Track storm location, size, cloud patterns; cannot measure winds directly

-Cloud-top temperatures indicate convection intensity (colder → stronger)

-QuikSCAT measures surface winds; multiple satellites estimate precipitation

-Dvorak technique estimates intensity from imagery

-Provides continuous, large-scale monitoring

Eyewall Replacement Cycles

-Inner eyewall convection replaced by outer ring; may repeat multiple times

-Examples: Allen (1980), Andrew (1992), Wilma (2005)

-Cycles can temporarily weaken or strengthen storms, affecting forecasts

African Dust - SAL

-Dry, dusty air layer from Sahara overlaying cooler Atlantic air

-Contains dry air & mineral dust; linked to midlevel easterly jet & inversion

-Can inhibit storm development (dry air, inversion, wind shear)

-Storms may intensify rapidly once out of SAL

-Major factor suppressing or delaying Atlantic hurricanes